Elastic fluid generator



by s torrwey.

Inventor: VVil liam LREmmet,

a u u .0. .0 C

llllllllllllllllllllllll Il Jan. 14, 1941.

Patented Jan. 14, 1941 UNITED STATES ELAsTic FLUID GENERATOR William L. R.. Emmet, Schenectady, N. Y., assignor to General Electric Company, ay corporation of New York Application June 25, 1938, Serial No. 215,827

5 Claims.

The present invention relates to elastic uid generators in which uid is heated in tubes lining the wall of a heating chamber or furnace. More particularly, the invention relates to generators in which uid is heated to high temperatures of the order of 1000 F., as is the case in mercury boilers. These high temperatures cause considerable expansion of the heating tubes and relative movement between them and the walls of the heating chamber adjacent thereto. The relative movement between the heating tubes and the walls necessitates the provision of special means for supporting both the tubes and the walls and for guiding the tubes and maintaining their relative position during operation.

The object of my invention is to provide an improved construction and arrangement of elastic uid generators of the type above specified whereby heating tubes lining the walls of a heating chamber are free to expand relative to the insulating wall of the chamber and are retained in their proper relative positions.

For a consideration of what I believe to be novel in my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing Fig. 1 illustrates a mercury boiler embodying my invention; Fig. 2 is a section along the line 2-2 of Fig. 1; and Fig. 3 is a section along the line 3-3 of Fig. 1.

'Ihe arrangement comprises an annular row of heating tubes I0 defining a combustion chamber II. Intermediate portions I2 of the tubes are curved inward towardsthe center of the chamber and spaced to permit the discharge of combustion gases. Upper portions I3 of the tubes form several parallel rows connected at their upper ends to a vessel or drum I4. Each tube has an extension I5 with a downwardly curved end portion located within the drum to eiect discharge of heated fluid in downward direction within the drum towards a pool I 6 of mercury formed in the drum and thereby to minimize the discharge of liquid particles through a discharge conduit I'I connected to the drum I4. The lower ends of the tubes I 0 are connected to a lower header I3 to which mercury liquid is supplied by down-comers I9 connected between the headers I8 and the drum I4. The heating tubes and the drum are surrounded by a wall or walls 20 of heat-insulating and heat-resistant material and these walls are enclosed by a sheet metal casing 2l. The lower portion of the wall 20 may consist of several layers or sections 22, 23 of different kinds of heat-resistance and heat-insulating material, as is common in boiler practice. The lower or straight portions of the tubes I0 forming the combustion chamber I I are substantially vertically arranged and line the walls 20 while the upper portions I3 of the heating tubes are disposed centrally within the space defined by the walls 20. A boiler of this general type is disclosed in my copending application, Serial No. 221,119-, i'lled May 17, 1935, and assigned to the General Electric Company.

During operation, mercury liquid is conducted through the down-tubes I9 to the lower headers I8, whence it ows up through the up-tubes I0 and is partly evaporated, the mixture of liquid and vapor being discharged through the curved extensions I5. The liquid thus discharged is re-circulated and the vapor is discharged through the vapor conduit I'l.

The heating in the chamber I I takes place primarily by radiation, whereas the heating of the upper straight portions I 3 of the tubes takes place primarily by convection. In order to provide a circuitous path for the combustion gases leaving the chamber II and to cause these gases to flow across the upper tube portions I3, I provide baflles 24 and 25 connected to opposite portions of the wall 20 and made of heat-resistant material. Portions of these bailies are supported on spaced collars 26 and 21 formed on the upper tube portions I 3. 'I'he bottom portion of the drum I4 is also covered by heat-insulating material which is partly supported by means of collars 28 welded to the tube portions I3.

During operation, mercury is heated in the tubes I0 at temperatures of the order of 1000o F. This, as stated before, requires special supporting means for the tubes and the walls, permitting relative expansion between them. In the present arrangement each tube is provided with a laterally extending supporting lug 29 ne'ar the upper en d of the combustion chamber. These lugs extend radially outward into the wall 20 and are secured to the tubes by welds 39. Thus the annular row of tubes is provided with a plurality of separate supporting lugs welded to the back of the tubes (Fig. 2). The lugs rest on a supporting member, bar or ring 3I partly embedded in the insulating wall 20 and having an outer cylindrical surface with four uniformly spaced projections 32, each projection including two side walls 33 and 34 secured to the supporting ring 3| by welds 35 and a bottom plate 36 secured to the walls 33, 34 by welds 31. The supporting ring 3| with the projections 32 are yieldingly held on a fixed support. The xed support includes horizontal beams 38 secured to vertical beams 39, which latter rest on a foundation 40. The connection between the beam structure and the projections 32 comprises Vertical rods 4I held at their upper end on the beams 38 and compression springs 42 surrounding lower portions of the rods 4I and engaging attheir upper ends the bottom plates 36 and at their lower ends end plates or washers 43 held on the rods.` Each spring 42 is enclosed in a casing 43a welded at its upper end to the bottom plate 38. rangement the tube structure, particularly the portions of the tubes lining the wall in the combustion space, is yieldingly supported by means external the boiler wall. The upper tube portions I3 are supported on the drum, which latter is held on upper beams 44 by means of U-shaped links 45. With the support of the tubes on the drum and near the upper end of the combustion chamber, the shape of the curved tube portions I2 and the spacing of these portions is maintained during operation. In other words, the support of the vertical tubes lining the combustion chamber near the upper end thereof prevents the vertical tubes from exerting downwardly directed forces on the curved tube portions I2.

As shown in Figs. 2 and 3 the tubes are slightly spaced circumferentially, It is important to maintain this spacing and also to prevent the tubes from curving inward towards the combustion chamber during operation in order to effect uniform heating of the tubes and to prevent burning of the Walls 28. This is accomplished by the provision of means for guiding the tubes on the wall 2l). This means, as will be seen presently, also serves to support the walls 2D on the supporting ring 3l. Each tube is provided with several vertically spaced guiding lugs 4G, each lug being in the form of a U-shaped member with the legs thereof welded to the tube and the base disposed vertically in a corresponding recess 41. Embedded in the Wall 28 and projecting into the recesses 4l thus formed are several vertically spaced rings 4.8. The U-shaped guide lugs, more specifically thekvertical base portions thereof project through openings 49 in said rings. The vertically spaced rings are welded to vertical supporting rodls 50 which have their upper ends united with the supporting ring 3l by means of welds 5I. The supporting rods 5I] with the rings 48 serve to guide the tubes Ill in the combustion space and to support the wall 28 Thus the rings 48 constitute both guide members for the tubes IU and supporting members for the wall 2G. The rods 50 are substantially surrounded by the insulating wall but slightly spaced therefrom to permit relative expansion-between the material of the wall and the rods.

As stated above, each guiding lug 4S is located in a recess 4l. The circumferential widlth of the recess is only slightly greater than the thickness of the lug 45, Adjacent recesses are separated by heat resistant wall portions 52. These wall portions form stops for the guide lugs 46, permitting only slight circumferential movement of the guide lugs and the tubes fastened thereto relative to the wall 20, Thus the circumferential spacing of the tubes will be maintained during operation by the stops formed by wall portions 52 intermediate adjacent recesses. The outer surface of the wall 20 is enclosed by the sheet metal casing 2| which comprises an upper portion 53 surrounding the upper portion of the wall 2U and the drum I4 and -a lower portion .54 surrounding the wall ofthe.

With this arcombustion chamber II and welded to the supporting ring 3 I. The upper end of the casing portion 54 forms a sliding joint 55 with the lower end of the casing portion 53. With this arrangement the outer casing is free to expand relative to the insulating wall 20 and also relative to the heating tubes I0. The heating tubes I0, the wall 2l) and the lower casing portion 54 for the combustion chamber have a common supporting means including the supporting ring 3I.

n As stated above, means are provided to limit circumferential relative movement between the tubes and to guide the tubes along the wall and thereby to reduce the tendency of the tubes to curve inward towards the combustion space. As an additional means to maintain the tubes taut and in vertical alinement, I provide a lower bottom wall or casing portion separate from the walls 20 andi hung or supported on the lower ends of the tubes.

In the present instance I have shown a bottom 56 for the boiler forming an opening 5'I for the supply of fuel and air and supported on an end or bottom plate 58. The latter is held on a plurality ofV rods 59 having lower portions welded to the plate 58 and upper portions welded to the annular header I8, the latter being embedded in the bottom wall 56. With this arrangement the bottom wall may move vertically relative to the side wall 20 and be supported substantially entirely on the lower ends of the tubes I0, 'I'he latter will maintain their vertical position during operation.

Means forming a sliding joint 60 are provided to seal the outer wall 20 against the bottom wall in order to prevent leakage of air into the combustion chamber. Certain features of the arrangement described above form a part of the application of O. L. Wood, Jr., Ser, No. 221,315, iiled July 26, 1938 and assigned to the same assignee as the present application.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A boiler including the combination of walls forming a heating chamber, a row of heating tubes lining the wall in said chamber, and means including lugs secured to upper portions of the tubes and projecting radially outward and a supporting member for the lugs for yieldingly supporting the tubes and the wall, the tube portions below the lugs` being free to expand in downward direction relative to the walls.

2. A boiler including the combination of a wall forming a heating chamber, a row of vertically disposed heating tubes lining the wall in said chamber, and means for yieldingly supporting the tubes and the wall and permitting relative vertical expansion between them during operation comprising lugs secured to upper portions of the tubes and projecting outward into the wall, a fixed support and means including a member engaging the lugs and having a plurality of lateral projections and a spring yieldingly supporting the projections on the fixed support.

3. Aboiler including the combination of a wall forming a heating chamber, a row of vertically arranged tubes lining the wall in the heating chamber being free to move relative to the wall, means securing upper portions of the tubes to adjacent portions ofthe wall, and means forming a refractorylined bottom to the heating chamber, and means for supporting the refractory lined bottom on the lower ends of the tubes for keeping the latter taut.

4. A boiler including the combination of a wall forming a heating chamber, a row of vertically ar forming a combustion chamber, closely spaced vertically arranged tubes lining the Wall in the chamber, a casing enclosing the wall, and means external the chamber and lugs secured tothe upper ends of the tubes for supporting the tubes and the wall and the casing and permitting relative 5 movement between them.

WILLIAM L. Ri. EMMET. 

